As for an in-focus position detection method that detects a distance to a main subject, there is a contrast method or a phase difference auto focus (“AF”) method. The phase difference AF method is frequently employed in a single lens reflex camera since it is capable of performing the in-focus position detection with high speed and high precision as compared to the contrast method.
A phase difference AF method employed in a conventional single lens reflex camera, for example, as disclosed in Patent Literature 1 below, is provided with two phase difference detection line sensors disposed at the left and the right sides separately from a solid state image capturing element that captures an image of a subject and detect a distance to a main subject based on a phase difference between the detection information of a first line sensor and the detection information of a second line sensor.
The phase difference AF method disclosed in the Patent Literature 1 has problems in that detection line sensors for use in detecting a phase difference are needed separately from a solid state image capturing element and, thus, the component costs and the manufacturing costs are increased, and further the size of the apparatus becomes larger.
Accordingly, as disclosed in Patent Literature 2 below, it has been proposed to install phase difference detection pixels on a light receiving surface of the solid state image capturing element. Since a solid state image capturing element formed with phase difference detection pixels is employed as for a solid state image capturing element that captures an image of a subject, an external phase difference detection sensor becomes unnecessary and cost reduction becomes enabled.